FIELD OF THE INVENTION
The invention relates to FCC processes using a high fluid throughput and low pressure drop, liquid atomizing process and apparatus. The process comprises forming a two-phase fluid mixture of the hot feed oil and a dispersion gas, such as steam, dividing the fluid into two separate streams which are simultaneously passed under pressure, through (i) an impingement mixing zone, and then (ii) a shear mixing zone, to form a single stream which passes into (iii) a lower pressure atomizing zone, in which atomization occurs to form a spray of atomized drops of the liquid. The apparatus comprises a nozzle in which the impingement and shear mixing zones comprise a single cavity.